Re: [PATCH 1/2] leds: add DT binding for BCM6328 LED controller

[Florian Fainelli <f.fainelli@gmail.com>]

On 02/04/15 04:54, Álvaro Fernández Rojas wrote:
> This adds device tree binding documentation for the Broadcom BCM6328 LED
> controller.

Looks pretty good to me, few comments below:

> 
> Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
> Signed-off-by: Jonas Gorski <jogo@openwrt.org>
> ---
>  .../devicetree/bindings/leds/leds-bcm6328.txt      | 173 +++++++++++++++++++++
>  1 file changed, 173 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/leds/leds-bcm6328.txt
> 
> diff --git a/Documentation/devicetree/bindings/leds/leds-bcm6328.txt b/Documentation/devicetree/bindings/leds/leds-bcm6328.txt
> new file mode 100644
> index 0000000..e63d27f
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/leds/leds-bcm6328.txt
> @@ -0,0 +1,173 @@
> +LEDs connected to Broadcom BCM6328 controller
> +
> +Required properties:
> +- compatible : should be : "brcm,bcm6328-leds".

Something like "brcm,bcm6328-leds-ctrl" might be a bit more descriptive.

> +- #address-cells: must be 1
> +- #size-cells: must be 0
> +- reg: BCM6328 LED controller address and size.
> +
> +Optional properties:
> +- brcm,serial-leds: enable Serial LEDs.
> +
> +Each led is represented as a sub-node of the brcm,bcm6328-leds device.
> +
> +LED sub-node properties:
> +- reg : LED pin number (could be from 0 to 23).
> +- compatible : should be : "brcm,bcm6328-led".

Do we really need to strongly type the LED child nodes here with a
compatible string? It is somewhat implicit that if your parent is
"brcm,bcm6328-leds", the child nodes are of the same "type"?

> +
> +Normal LED:
> +- label (optional) : see Documentation/devicetree/bindings/leds/common.txt
> +- active-low (optional) : LED is active low.

If it is an optional property, you would want to clarify that active
high is the default.

> +- default-state (optional): see
> +  Documentation/devicetree/bindings/leds/leds-gpio.txt
> +- linux,default-trigger (optional): see
> +  Documentation/devicetree/bindings/leds/common.txt
> +
> +Hardware controlled LED:
> +- brcm,hardware-controlled (optional) : LED is hardware controlled.

The type of this property is not strictly defined, but it would appear
to be a boolean. Reading through the driver though, it looks like the
number of LEDs "hardware" controlled should be something customizable at
some point.

> +- brcm,link-selection (optional) : LED link selection values.

Here you should specify exactly which values are accepted, if this is a
value that is directly mapping to a hardware register value, we might
want to create a header file for that.

> +- brcm,activity-selection (optional) : LED activity selection values.

Ditto.
-- 
Florian